1. Field
One or more embodiments include one or more storage tanks with at least one side being designed to have a super elliptical, one or more embodiments include one or more storage tanks in a chemical system that are designed to have at least one side be super elliptical shaped, one or more embodiments include storage tanks designed to have at least one side be super elliptical shaped in a redox flow battery system, and one or more embodiments of such a redox flow battery system that include one or more strings of storage tanks designed to store electrolyte and have at least one side be super elliptical shaped for increased storage efficiency and improved self-support.
2. Description of the Related Art
Large outdoor storage tanks are usually made of steel and mounted on concrete pads. Large indoor chemical storage tanks are often made of stainless steel or polypropylene and may be mounted on a concrete floor or be rack mounted. Most large storage tanks are in the shape of a vertically mounted cylinder having a horizontal cross-sectional area in the shape of a circle. It is generally of advantage to keep the height of the tank to a minimum in order to minimize the fluid pressures near the bottom of the storage tank. It is also generally of advantage to reduce the ground or floor area occupied by the storage tank to reduce the real estate costs, balanced with a height of the storage tank and desired volume of fluid being stored.
Buildings are generally rectangular in shape and therefore typically have floors that are laid out in rectilinear patterns. Outdoor real estate is also generally laid out in rectilinear plots of ground. To make maximum use of available floor space or outdoor real estate it would be most efficient to use storage tanks that have a square or rectangular cross-section. However, because of internal fluid pressures, the lateral (or vertical) sides of large square or rectangular storage tanks would typically bulge outwards unless the storage tank walls were made exceptionally thick and rigid. Storage tanks are therefore generally made to have a circular cross-section to minimize the material requirements, as a circle cross-section provides substantial self-support for the storage tank typically counteracting such internal fluid pressures.
A circular cross-section tank resting on a rectangular floor layout occupies a square area of floor space. Thus, the floor area between the circular tank area and the circumscribed square floor area represents wasted floor space. For a circle or an ellipse this represents 21.5% of wasted floor space. This wasted space could be partly recovered by using a square (or rectangular) tank having rounded corners. Although this geometry would recover a significant portion of the wasted space between the circle and the square, it leaves the tank with long un-curved wall segments that must be reinforced to resist the internal fluid pressures.
The above discussion applies equally to circular cross-section tanks and their circumscribed squares, and to elliptical cross-section tanks and their circumscribed rectangles. Circles are a special case of the more general elliptical shape, so the discussions which follow will focus on elliptically shaped cross-section tanks, even though elliptical tanks are rather rare in tank designs.